- Raise and suitably support the vehicle. Refer to
Lifting and Jacking the Vehicle.
- Remove the nuts securing the catalytic converter to the right exhaust manifold.
- Lower the vehicle.
- Remove the spark plugs. Refer to
Spark Plug Replacement for the 5.3L engine or
Spark Plug Replacement for the 6.0L engine.
- Remove the heat shield bolts, and shield from the exhaust manifold.
- Remove the exhaust manifold bolts, manifold, and gasket.
- Discard the gasket.
- Clean and inspect the exhaust manifold. Refer to
Exhaust Manifold Cleaning and Inspection for the 5.3L engine or
Exhaust Manifold Cleaning and Inspection for the 6.0L engine.
Installation Procedure
Important:
• | Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or On-Board Diagnostics (OBD) II system performance. |
• | The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material. |
Notice: Refer to Fastener Notice in the Preface section.
Important: Do not apply sealant to the first 3 threads of the bolt.
- Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
- Install the exhaust manifold NEW gasket and bolts.
Tighten
- Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
- Tighten the bolts a final pass to 25 N·m (18 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
- Install the heat shield, and bolts to the exhaust manifold.
Tighten
Tighten the bolts to 9 N·m (80 lb in).
- Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the front of the right cylinder head.
- Install the spark plugs. Refer to
Spark Plug Replacement for the 5.3L engine or
Spark Plug Replacement for the 6.0L engine.
- Raise the vehicle.
- Install the nuts that secure the catalytic converter to the left exhaust manifold.
Tighten
Tighten the nuts to 50 N·m (37 lb ft).
- Lower the vehicle.